Small desire or fancy (5)
I believe the answer is:
swish
'fancy' is the definition.
Both the answer and definition are adjectives. Perhaps you can see a link between them that I don't see?
'small desire' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'desire' becomes 'wish' (wish is a kind of desire).
's'+'wish'='SWISH'
'or' is the link.
Can you help me to learn more?
(Other definitions for swish that I've seen before include "Impressively fashionable" , "Smart; stylish" , "Elegant" , "Sound of cane" , "Extravagant" .)